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u‰‰‘è–ÚF@High-Pressure Phase Transitions of Low-Coordination Oxides

u@Žt F@Prof. Karl Syassen
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The combination of high-resolution synchrotron x-ray diffraction, optical spectroscopies, and large hydrostatic pressures produced by diamond anvil cells offers a unique approach to studying structural, vibrational, and band structure related properties of solids. Since the introduction of the DAC, high pressure investigations of oxide materials have remained at the forefront of experimental high pressure research. This talk will be concerned with recent pressure studies of phase transitions in oxides [1-4] which have in common a low coordination of their ambient pressure phases. Topics to be discussed are the rich PT phase diagram of the spin-Peierls compound CuGeO$_3$ and new insights into pressure-induced amorphization of berlinite-type compounds, as obtained from combined x-ray diffraction, optical spectroscopy and Moessbauer studies.

[1] A. R. Goni et al., Phys. Rev. Lett. 77, 1079 (1996).
[2] S. Braeuninger et al., Phys. Rev. B 56, R11357 (1997).
[3] M. P. Pasternak et al., Phys. Rev. Lett. 79, 4409 (1997).
[4] T. Zhou et al., Phys. Rev. B 57, Jan. 1, 1998.

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¢˜bl@’†Œ´ƒˆê˜Y
Tel: 011-706-6929 Fax: 011-717-9304
E-mail: jun@phys.sci.hokudai.ac.jp

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